ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades short circuit??

I'm sure like me you all think if you put a short across the mains you will get a big flash and a bang and end up with a blow circuit fuse. I saw a video on YouTube where 2 Ukrainian guys apparently shorted out the mains to there shack and although the light went out and you can here the meter growling and buzzing as soon as the short is removed the supply returns as normal so my question is how did they do it and secondly am I aloud to put the name of the video on here not sure about forum rules for this

I suppose this could happen on a close to terrible supply with extremely high impedance, probably combined with overfusing. The short draws enough current to pull the voltage almost down to zero but doesn't blow any fuses because the short circuit current is never reached. If that shack is say on a long run of 6 mm2 aluminium the max. short circuit current could well be as low as 100 A and that's decidedly not enough to blow something like a 20 or 25 A fuse.

I'm not aware of any forum rules that'd keep you from linking to such a video.

It's obvious that the available current wasn't enough to clear any protective device(s) OR that short wasn't as much of a short as you were led to believe. You will have to look at the time/current curves for the fuses to see when they should clear. One of my pet peeves is looking at a set of curves that doesn't show the time that the fuse should clear at 105%. I also just recently saw a set where several of the curves crossed.

The video is at YouTube kreosann look for one called we don't need fireworks we have electricity you may need to try different versions of the same videos as some have English subtitles and speach some only ukranian or russian

I don't think the lights actually dim that much! The arc flash is so bright that the camera doesn't even register that tiny wall light any more. That's a normal effect with automatic exposure controls.

The fuses are likely gL Diazed but without knowing how many amps it's pointless to speculate. What I can tell you is that gL and gG fuses are fairly slow. Depending on their size they're supposed to trip at 1.6 to 2.1x rated current within an hour! The overload factor is larger with smaller fuses, 1.6 is only from 20 A up I think.

Thanks Texas ranger I'm guessing that with a combination of a slow ish fuse a high impedance supply you can put a dead short on the mains and it will not blow the fuse I've never come across this situation in real life but I'm guessing if you have a loop impedance of 2 ohms a supply of 220 volts that's 110 amps and a 60 amp fuse you'd get away with it although I thing anyone else on the same phase is going to be a bit annoyed with you

If he was across service conductors, it is very possible you would never operate an over current device. You are counting on the input to the primary of the transformer. I have seen some very interesting results from faults in service conductors.

Don't count on such a big supply! I'd vote for 25 A single phase 2-wire max. or maybe 3 ph (the meter looks too small for that though). I suppose they could be on something as bad as a kilometre of 10 mm2 Al wire (the Italians do 6 mm Cu overhead wiring TODAY, feeding entire apartment complexes!).

I saw in another of there videos that the little shack is on single phase you can see a 2 wire drop from the 3 phase line running nearby. I suppose a 25 amp feed would be OK for a little shack but I think it would be a struggle for a whole house. I'm surprised the Italians still do such things I can imagine the lights dimming every time you put the coffee machine on!

The Italians will happily put you on a 15 A single phase supply regardless of the size of your house! And yes, they've got serious voltage drop issues there! I remember my parents' Sony stereo playing cassettes slower and slower and finally shutting off!

You wouldn't believe with how little power you can actually get by!

A German spark who eventually moved to Italy told me the story of the whole new housing estate. He ran something like 95 mm2 because the line was longish. Then came ENEL and installed a full kilometre of 6 mm2 overhead wire! He was a bit peeved I'd say

15 years ago I spent an exchange week in a 1970-ish flat in Torino. One evening my host mom had dinner in the oven and my host sister went to take a shower while I was sitting in my bedroom reading. Suddenly the whole place went dark because the combination of electric oven and water heater were too much for the 15 A mains! There were no individual MCBs or fuses, just a main 15 A RCBO built into the meter base!

OMG il never moan about our supply again its surprising just what some authorities will allow I remember going to a place near Dinard in France and the coach driver telling us not to be surprised if the power went off apparently they experienced regular powercuts there was 2 in the space of 2 hours and lots of lamp flicker awful when you think about it

Hi Annemarie I have seen that video, as I am very active in youtube as well , watching and making video's.
That shack they live in has a long overhead line. The supply is single phase 220 Volts 16 Amperes. They take power from before the diazed fuses or mcb on that old meter panel. There is a shot of the meter nameplate in one of their video's. Rating 5 - 17 Amps. They have also some crazy capacitor blow up video's too.

Many years ago in a cheap hotel in Bangkok I noticed the table lamp had a join in its figure 8 flex. I thought, "That looks a bit dodgy", and picked up the flex (after the join). Suddenly the room light went out followed by the flex glowing red hot below the join until it melted. Room light came back on and room full of acrid smoke.
Using my trusty neon screwdriver I carried I was able to remake the now somewhat shorter lead.

Hi RODALCO I didn't notice the rating plate on the meter I will look more carefully again I understand that in Russia and Ukraine they don't have LV fuses after the local transformer so I think if you bypass the fuses in your house the only protection is the fuses on the HV side of the transformer and they will never blow. I've seen those videos of them putting electrolytic caps straight across 220 volt mains they make a bit of a BANG Lol. I've seen your videos too I enjoy very much thanks for all your efforts. Winston I think bankok electrics must be as bad as Ukrainian ones must of been a scary moment

Well there's a reason why elderly people (who've experienced Russian occupation after WWII) around here call dodgy wiring (and other stuff) "Russian". I've seen absolutely spotless Russian work though, conduit run with an iron, as were the wires inside the consumer unit.

I do think these folks have LV fuses but try blowing say a 250 A fuse if you're on a long overhead supply!

I followed kreosan's videos for quite some time - it's two guys in a region that has been hit hard by some sort of military action. Basically, they've already been through enough that they're more or less desensitized to any "danger" from electricity.

If we're talking about the video I'm remembering, yes, they did short the mains, right off the meter, but using a considerable length of wire, which glowed red hot before finally melting. It is my suspicion that the wire was thin enough and long enough to have a resistance sufficient to keep the actual short current below the rating of whatever protective device may have been upstream of it.

Also, I know not all countries are the same as the US, and some have fuses or breakers before the meter -- but I was picturing there /not/ being one there, and the short being placed on the line side of the meter.

As to the lights going out -- I suspect the camera exposure as mentioned by someone else.

I'm sure it's a combination of all the things mentioned here. I saw a video recently showing Russian workers replacing a xformer and in the LV cabinet there was a 3 phase switch and 3 diazed fuses so looks like they do have LV fuses afer all I can't put a link because the title of the video and the person who put it there was all in Russian language so not a clue what it said. Also the cabinet where the fuses were had a hand painted rating label on much like the one in Siberian odysee posted on this forum ages ago.

Emolator did you see the one where they put an ammeter across the mains just after the meter?

Hi, would you share the YouTube username or a link to one of these videos? thanks.

Hi Andy look for YouTube kreosann there are about 57 videos on there site now if you speak ukranian or Russian you will be fine otherwise you mite need to search for videos that have English subtitles or commentar added have fun watching!

Hi andey, Some Youtube links to some of Kreosan's video's attached.
Real cool stuff to watch and the Russian commentary is awesome, English subtitles supplied as well on some video's.

https://youtu.be/P9xair-t-Es

The glowing wire.

https://youtu.be/ahQIQxq8JY4

The ammeter

Awesome, thanks!